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What's a Joker, and you're going to do what?!

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The MX5 Cobra is out of the shed, so room for my next project 👍 MX5 Cobra project (see NZ Japanese Cobra blog) is all done bar the painting (soon hopefully). So, it makes way for my next project... Electric Conversion of a Classic Scooter So, I was toying with the idea of getting an electric bicycle to ride to work (on nice weather days 😃), but... wow, aren't they expensive for what you get! I then looked at electric scooters (moped scooters). For not much more than the cost of an electric bicyle you can get an electric scooter, but not a very nice looking one (like a Vespa or similar classic scooter). Then I remembered that before I decided to do the MX5 Cobra I liked the idea of doing an electric car conversion - so, light bulb moment - let's do an electric scooter conversion! A bit of research later to see how feasible it would be, estimating likely costs, etc, and the project was a go. But, what scooter should I convert? Obviously, the name "Vespa&qu
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Do the "Electro Scoot" scooters actually work?

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Donor "Electro Scoot" electric scooters
"Electro Scoot" scooters

Ok, time to see what's required to get one of these "Electro Scoot" scooters working. The chap I bought them off said he was using the red one for a while, so let's have a go at that one first.

Took the seat and a few covers off and actually found it has five 12 volt, 20Ahr sealed lead acid (SLA) batteries in it.
Electric scooter with seat and covers removed
Red e-Scooter with seat and covers removed

The batteries were connected in series, so the scooter uses 60 volts for power with 20 amp hours of battery capacity. Checked the batteries and tried charging them, but they were stuffed. Obviously been sitting for too long without being charged.

Time to find some new batteries. I did a bit of research and found:

>  Replacement 12 volt Sealed Lead Acid (SLA) batteries, deep cycle ones, of similar capacity were around $125 each (so $625 just to see if the bikes work!). However, the SLA batteries are 6.5kg each, so they add 32.5kg of weight to the bike. Also, charging 5 batteries in series with a single 60 volt charger isn't good for the batteries. It is hard to get the same charging voltage and current across all of the batteries, so there is a danger of over-charging some batteries and under-charging others. A better option is to use 5x 12V battery chargers, but that makes for a bit of a messy charging set-up.

> Replacement 12 volt Lithium batteries (18 Ahr) were $289 each. Same physical size as the old SLA batteries, so no space saving. But, they're 2.6kg each, so would save 19.5kg in weight. However, they would still have the same charging issue when charging the batteries connected in series.

> Finally, I found a 60 volt, 10Ahr Lithium battery pack for $387 (plus $81 for a 60V lithium battery charger). Two batteries would be required to get the same 20 Ahr capacity, but I've just bought one for now (one now for testing and if all good then I'll get a second one). Weight saving for two batteries would be a whopping 22.3kg (as they're only 5.1kg each), plus there's no issues with charging the two batteries in parallel. Also, look at the space saving:

Electric scooter's original lead acid batteries
Space taken up by the 5x SLA batteries

Electric scooter with new lithium battery
Space taken up by the single 60V lithium battery (yes, the blue square!)
 
So, plenty of room for two 60V Lithium batteries - could even be room for three!

Right, time to secure the new 60V battery in place, hook it up to the existing wiring, turn it on and see what happens...


It works!

Top speed is around 45km/hr, but quick acceleration through to about 30km/hr. However, these Electro Scoot scooters are a very unstable scooter! The front wheel set-up isn't castered, so tracking a stable path is near on impossible. Looking forward to moving the electric bits into a decent frame... see next post



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